This study is designed to investigate the pharmacokinetic/pharmacodynamic models of the physioloigical and psychological effects of intravenous administration of cocaine. The pharmacodynamic effects of interest include cardiovascular, subjective, and electroencephalographic effects. This will be a single blind inpatient study in which saline and 20mg and 40mg doses of cocaine will be administered intravenously in a pseudo-random fashion. Six healthy subjects with a history of recent cocaine abuse, who meet criteria for cocaine abuse or dependence but are currently not dependent on any other substance except nicotine will be studied in this investigation.